Advertisement

08.15.2008 at 10:31AM PDT, ID: 23651997
[x]
Attachment Details
[x]
The Solution Rating System

With so many solutions, how can you tell which solutions are most likely to help you and which ones are not? To provide you with a tool to use, we rate our solutions based on various elements that most accurately determine if a solution is a quality solution. To explain what factors affect the solution rating, here are the elements we take into consideration when formulating our solution rating.

  • The Grade of the Solution
  • The Zone Rank of the Expert Providing the Solution
  • The Number of Author and Expert Comments
  • The Number of Experts Contributing
  • The Feedback of the Community

Your Input Matters
Because of the way the system is set up, the most important variable in this equation is you. As a member of Experts Exchange, you are able to cast your vote on the quality of the solutions in regard to how complete, accurate, helpful and easy to understand each solution is. When you provide your feedback, each rating is adjusted accordingly. So, if you see a solution that has a poor rating that you think is a good solution, let us know by rating it. As you do, the rating will be adjusted and will become more accurate for other members of our site.

If you have any suggestions that you would like to make for our rating system, please ask a question in the Suggestions Zone of Community Support.

Thank you!
9.0

Iptables and FTP upload

Asked by develc in Network Software Firewalls, Linux, Linux Networking

Tags:

Hello Experts,

I have an iptables script in a Linux powered client machine. It works, except for uploading data over ftp, it hangs at 100%. Examining with wireshark I am getting destination unreachable icmp packets. Turning off the firewall solves the problem. The ftp connection is passive connection. What am I missing, and how can I solve this problem securely? My script is belowStart Free Trial 
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:

#!/bin/bash
IPTABLES=/sbin/iptables
MODPROBE=/sbin/modprobe
INT_NET=192.168.0.0/255.255.255.0
 
### load the modules
echo "[+] Loading modules..."
$MODPROBE nf_conntrack
$MODPROBE nf_nat
$MODPROBE nf_conntrack_ftp
$MODPROBE nf_conntrack_ipv4
$MODPROBE nf_nat_ftp
 
### flush existing rules and set chain policy setting to DROP
echo "[+] Flushing existing iptables rules..."
$IPTABLES -F
$IPTABLES -F -t nat
$IPTABLES -X
$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP
 
###### INPUT chain ######
echo "[+] Setting up INPUT chain..."
### state tracking rules
$IPTABLES -A INPUT -m state --state INVALID -j DROP
$IPTABLES -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
### anti-spoofing rules
$IPTABLES -A INPUT -i eth0 -s ! $INT_NET -j DROP
### ACCEPT rules
$IPTABLES -A INPUT -i lo -j ACCEPT
$IPTABLES -A INPUT -i eth0 -s $INT_NET -j ACCEPT
$IPTABLES -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
$IPTABLES -A INPUT -j DROP
 
###### OUTPUT chain ######
echo "[+] Setting up OUTPUT chain..."
### state tracking rules
$IPTABLES -A OUTPUT -m state --state INVALID -j DROP
$IPTABLES -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
### ACCEPT rules for allowing connections out
$IPTABLES -A OUTPUT -o lo -j ACCEPT
$IPTABLES -A OUTPUT -o eth0 -d $INT_NET -j ACCEPT
#FTP
$IPTABLES -A OUTPUT -p tcp --dport 20 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 21 --syn -m state --state NEW -j ACCEPT
#SSH
$IPTABLES -A OUTPUT -p tcp --dport 22 --syn -m state --state NEW -j ACCEPT
#SMTP
$IPTABLES -A OUTPUT -p tcp --dport 25 --syn -m state --state NEW -j ACCEPT
#Whois
$IPTABLES -A OUTPUT -p tcp --dport 43 --syn -m state --state NEW -j ACCEPT
#HTTP
$IPTABLES -A OUTPUT -p tcp --dport 80 --syn -m state --state NEW -j ACCEPT
#HTTPS
$IPTABLES -A OUTPUT -p tcp --dport 443 --syn -m state --state NEW -j ACCEPT
#MSN
$IPTABLES -A OUTPUT -p tcp --dport 1863 --syn -m state --state NEW -j ACCEPT
#RTMP
$IPTABLES -A OUTPUT -p tcp --dport 1935 -m state --state NEW -j ACCEPT
#Google talk
$IPTABLES -A OUTPUT -p tcp --dport 5222 --syn -m state --state NEW -j ACCEPT
#IRC
$IPTABLES -A OUTPUT -p tcp --dport 6667 --syn -m state --state NEW -j ACCEPT
#Skype
$IPTABLES -A OUTPUT -p tcp --dport 23399 --syn -m state --state NEW -j ACCEPT
#DNS
$IPTABLES -A OUTPUT -p udp --dport 53 -m state --state NEW -j ACCEPT
#NTP
$IPTABLES -A OUTPUT -p udp --dport 123 -m state --state NEW -j ACCEPT
#IPP
$IPTABLES -A OUTPUT -p udp --dport 631 -m state --state NEW -j ACCEPT
#RTMP
$IPTABLES -A OUTPUT -p udp --dport 1935 -m state --state NEW -j ACCEPT
#ICMP
$IPTABLES -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
$IPTABLES -A OUTPUT -j DROP
[+][-]08.15.2008 at 02:51PM PDT, ID: 22241957

Assisted solutions are selected by the member who asked the question as a comment that contributed to their question's solution.

Start your 7-day free trial to view this Assisted Solution or ask the Experts your question.

 
[+][-]08.15.2008 at 04:27PM PDT, ID: 22242394

At Experts Exchange, members can ask their questions to thousands of technology professionals, also known as Experts. Experts compete and collaborate to answer those questions by leaving comments like this one.

Start your 7-day free trial to view this Expert Comment or ask the Experts your question.

 
[+][-]08.15.2008 at 04:36PM PDT, ID: 22242451

At Experts Exchange, members can ask their questions to thousands of technology professionals, also known as Experts. Experts compete and collaborate to answer those questions by leaving comments like this one.

Start your 7-day free trial to view this Expert Comment or ask the Experts your question.

 
[+][-]08.15.2008 at 10:27PM PDT, ID: 22243206

Often, when Experts are collaborating with members who have asked questions, they will request additional information about the problem. Askers respond with an author comment like this one.

Start your 7-day free trial to view this Author Comment or ask the Experts your question.

 
[+][-]08.15.2008 at 11:16PM PDT, ID: 22243306

View this solution now by starting your 7-day free trial. Setting up your free trial is quick, easy, and secure. We will return you to this solution, unlocked, when you're done.

 

About this solution

Zones: Network Software Firewalls, Linux, Linux Networking
Tags: iptables
Sign Up Now!
Solution Provided By: Kdo
Participating Experts: 2
Solution Grade: A
 
 
[+][-]08.16.2008 at 12:15AM PDT, ID: 22243408

Often, when Experts are collaborating with members who have asked questions, they will request additional information about the problem. Askers respond with an author comment like this one.

Start your 7-day free trial to view this Author Comment or ask the Experts your question.

 
[+][-]08.16.2008 at 04:54AM PDT, ID: 22243830

Often, when Experts are collaborating with members who have asked questions, they will request additional information about the problem. Askers respond with an author comment like this one.

Start your 7-day free trial to view this Author Comment or ask the Experts your question.

 
[+][-]08.16.2008 at 08:04AM PDT, ID: 22244286

Assisted solutions are selected by the member who asked the question as a comment that contributed to their question's solution.

Start your 7-day free trial to view this Assisted Solution or ask the Experts your question.

 
 
Loading Advertisement...
20081112-EE-VQP-42 / EE_QW_2_20070628